Disclosed in JP2008-6855A is an example of a known grille control mechanism for a vehicle. According to the grille control mechanism for the vehicle disclosed in JP2008-6855A, a movable member is provided between a front grille and a radiator of the vehicle, so that an aerodynamic characteristic of the vehicle, an engine temperature and the like is adjusted by adjusting inflow of air from a front portion of the vehicle to the radiator, in order to achieve a preferable driving performance of the vehicle. More specifically, the movable member is configured as a movable fin, which is pivotable about a horizontal axis. Accordingly, the inflow of the air is adjusted by controlling an air inlet passage to be opened and closed by the movable fin so that air resistance, lift force or downforce is applied to the vehicle in order to ensure a stable driving performance of the vehicle.
Disclosed in JPH5-50861A is another example of a known grille control mechanism for a vehicle. According to the grille control mechanism for the vehicle disclosed in JPH5-50861A, a movable member (a movable grille) is controlled to be opened and closed in response to an environmental condition (e.g. ambient temperature and the like) and an engine load condition (e.g. a temperature of an engine cooling medium and the like). The grille control mechanism for the vehicle disclosed in JPH5-50861A estimates an opening-closing state of the movable member, by which an appropriate cooling effect is supposed to be obtained under a certain environmental condition and the engine load condition, on the basis of plural determination conditions, which are stored within a storing means. Then, the grille control mechanism executes an opening-closing control of the movable member on the basis of the estimation result in order to adjust cooling of the engine cooling medium to be appropriate.
Both of the grille control mechanism disclosed in JP2008-6855A and the grille control mechanism disclosed in JPH5-50861A are intended to improve the cooling of the engine cooling medium, to achieve a driving stability of the vehicle and the like by controlling the movable member to be at the opened position or the closed position on the basis of each condition. Therefore, in a case where a mechanical error or malfunction occurs at a driving mechanism of the movable member because of, for example, an object being caught in the movable member, the operation in response to the control may not properly be executed.
In a case where an operation control of the movable member is maintained (continues) without recognizing the error or the malfunction of the movable member when the above-mentioned situation occurs, an excessive load may be applied to the movable member, an electric motor and the like, so that a damage may occur thereat. However, providing a potentiometer and the like to the grille control mechanism in order to check whether or not the movable member is controlled to be at a position as commanded may lead to an increase in manufacturing costs of the grille control mechanism for the vehicle, inflexibility in mountability of the grille control mechanism for the vehicle, and the like. Furthermore, in a case where an object which is easily removable, such as a pebble and the like, is caught in the movable member and the grille control mechanism determines the error or the malfunction occurs, a user may need to take an appropriate action, such as removing the pebble, every time when the grille control mechanism determines that the error or the malfunction occurs when the easily removable object is caught in the movable member.
A need thus exists to provide a grille control mechanism for a vehicle which is not susceptible to the drawback mentioned above.